• Category: web
• Points: 60
• Description:

Regular expressions are pretty useful. Especially when you need to search and replace complex terms.

Write-up

The given website is used to “Search & Replace” with regular expressions. From other challenges we know, that we can execute php code using:

/(.*)/e

(Check out this Stackoverflow answer for details.)

The problem was, that the website filtered some inputs like:

• file
• open

It worked with:

var_dump(show_source('flag.php'));

A simple, but nice challenge.

IW{R3Pl4c3_N0t_S4F3}